In the spectra of most biological samples, there are overlapping bands from different species. While standard multivariate calibration methods, most notably PLS, can extract individual analytes' concentrations with impressive accuracy, they cannot utilize the known spectrum of an analyte during the calibration process. We have recently developed a new calibration method called hybrid linear analysis (HLA) that incorporates the known spectrum into the calibration. Already we have seen that this method can generate equivalent or superior calibrations to PLS in predicting glucose in various media including blood serum. In our upcoming work, we will extend the application of this method to other analytes, as well as continue to explore the fundamental properties of the algorithm itself.